M18 IR Binocular

Background

The military has used Infrared night vision equipment since
it could be done, maybe WW1 and for sure WW2. In the 1960's there
were a large number of "sniper scope" IR devices and tubes offered on
the
surplus market. In the 1990's and 2000's there are a number of
M18
IR binoculars on the market.

Most military IR night vision equipment operates in what's called
near
IR. This means the wavelength is just a little longer than
visible
red light and is not visible to the unaided eye. To use near IR
equipment
you need some type of IR light source that typically is a visible light
source with an IR filter. The Xenon lights on armored tanks are
an
example. This is not a far IR viewer that can see things like
body
and engine heat. Far IR viewers are typically monocular and cost
in the thousands of dollars as used equipment and tens of thousands of
dollars new.

Unlike image intensifiers that will be burned by use in daylight,
you
can use the M18 in daylight, but it's performance is poorer than
ordinary
binoculars. This is an easy way to test them.

Following is an overview of how the M18 was used in Vietnam from
someone that was there.

The
Army sent four searchlight batteries to Vietnam, and the Marine Corps
had one. All were equipped with 23-inch Xenon searchlights, the
same searchlight that was mounted on the M-60 tank. Ours were
mounted on jeeps but frequently used other configurations -- on towers,
on ships, etc. The light was capable of a spread beam or a
focused beam, using white light or infrared light. The IR light
was made by mechanically rotating an infrared filter around the Xenon
bulb. The IR was invisible to the naked eye, but each searchlight
section was equipped with an IR monocular, called a metascope, and one
M-18 binocular. The IR searchlight would illuminate the area
several hundred meters to its front, and by watching through the M-18s
the operator could see reflected IR, with everything looking sort of
green but warmer objects, especially humans, appearing much
brighter green (the fact that humans tend to move also helped in their
detection). The searchlights were often paired with anti-aircraft
automatic weapons, specifically twin 40-mm "pom-pom" guns called
Dusters and quad-mounted .50-caliber machine guns called Quads.
When a target was identified, the M-18s were passed to the weapon
operator so he could point his guns in the general direction, then on
cue the searchlight operator would rotate the IR filter out of the way
and illuminate the target with white light. In sum, the
searchlight was an IR light source, and the metascope and M-18s were
light receivers.

My
platoon supported the US 9th Infantry Division in the Mekong Delta, and
about halfway through my tour I was called to the assistant division
commander's office to take possession of six "Pink Filters."
These were essentially identical to the IR filters, except that they
emitted a slightly different wavelength. They were optimized for
use with the first generation of light-amplification night vision
devices, the Starlight Scope and Night Observation Device. The
light they put out was still invisible to the naked eye, but could be
seen through those devices. We worked with snipers quite a bit,
extending the range of what they could see and hit, and providing an
area search capability that they lacked. As I recall, the "pink
light" could still be seen through the M-18 binoculars, but the images
were not as clear as through a Starlight Scope.

The
M-18s were expensive -- for some reason the figure $10,000 a pair
sticks in my mind. They also were capable of producing quite an
electric shock.

Jim
K

Operation

Install a BA-42 ("C" cell) into the battery compartment by
unscrewing the end of the battery compartment. Note that the cap
holds the ON-OFF switch. The battery goes in negative end first,
positive end toward switch.

Comments on operation

The pair that I have has some green fuzz when looking up at the night
sky.
The field of view is not totally black.
Putting Aluminum foil over the objectives with a rubber band shows
the left tube to have the green "fuzz" and the right tube to be much
more
black. I'll try at night when my eyes are night adapted.
Theoretically
you should be able to see satellites in near IR because the Sun is
illuminating
them. The question is how does this compare to ordinary night
time binoculars and image intensifiers for satellite viewing.

7 Aug 2002 - a power failure just at dusk was a good excuse to
utilize
a lawn chair to have an IR look upward. It's now clear that the
IR
binocs show planets but not stars. There were 4 planets out just
after sunset (I'm at 39N 123 W). I have since learned that these
must have been IR stars since there was only one planet visible at that
time.

No satellites were seen, but I'm now quite sure they will be
visible
in the IR binocs. Maybe people imaging space objects should pay
attention
to IR focus.

These binoculars can see IR Beacons
although
I think the beacons were designed for use with Night Vision Image
Intensifier
type equipment.

They can also see IR remote controls. The SDU-5/E
emergency strobe light with the IR cap installed appears to have a
bright
flash in the M18 but looks dead to your eye. This is true even if
the SDU-5/E is in the cloth pouch. Like in the movie "Blackhawk Down".

Because of the double mirror design when viewing an IR LED at
close
range it appears as a donut not a circle.